1. Field of the Invention
The invention relates to a vehicle seat provided with a cushion (i.e., a member that elastically supports an occupant).
2. Description of Related Art
Japanese Patent Application Publication No. 2001-70083 (JP 2001-70083 A), for example, describes one such known vehicle seat that includes a seat cushion, a seat back, and a headrest. The seat back is a member that is connected to the seat cushion, in a manner so as to be able to be reclined and raised, with respect to the seat cushion, and has a cushion that forms an outer shape of the seat. The cushion is a member that elastically supports an occupant, and includes a main portion and a pair of side portions. The main portion is a flat portion in the center of the cushion, and opposes the torso of a seated occupant. Also, the side portions are protruding portions that are positioned one on each side of the main portion, and protrude farther toward a seating side than the main portion. Each side portion includes an inner side portion that is adjacent to the main portion, and an outer side portion that is positioned on an outside of the inner side portion in a seat width direction. The main portion is divided laterally into two (i.e., an upper portion and a lower portion), and the inner side portion and the outer side portion are formed extending along both of the upper and lower portions of the main portion (i.e., continuous in the vertical direction of the seat).
In the related art, the outer side portions (i.e., the portions farthest to the outside in the seat width direction) are made of high hardness urethane foam. Also, the inner side portions and the main portion are made of urethane foam that has a lower hardness (i.e., is more flexible) than the outer side portions. In this way, during normal driving, the torso and shoulders and the like of the occupant are loosely supported by the inner side portions and the main portion that are low hardness portions, so a feeling of pressure on the occupant is able to be reduced. That is, the structure provides excellent seating comfort. Also, the occupant is firmly supported by the outer side portions that are high hardness portions, so the support performance of the seat is able to be maintained to a certain degree.
In the related art, the inner side portions are formed continuous in the vertical direction of the seat. Therefore, when pressure from the occupant is applied to a side portion (e.g., a lower portion of the inner side portion) or the like when the load of the occupant shifts when the vehicle is cornering or when the vehicle is involved in a collision, the support performance of the cushion may be insufficient.